Update: For more than a year, we've been covering the accusations against Harold Henthorn, who authorities say killed his wife, Dr. Toni Henthorn, by pushing her off Deer Mountain in Rocky Mountain National Park in 2012; see one of our previous reports below.

Today was expected to bring some closure for Toni's friends, family and loved ones.

After all, Henthorn was scheduled to be sentenced to life in prison — and he was.

But at a hearing before U.S. District Court Judge R. Brooke Jackson, Henthorn denied killing Toni even as an investigation continues into the possibility that he also ended the life of his first wife, Lynn Henthorn.

As we've reported, Lynn was killed in 1995 when she was crushed by a car that allegedly came off a jack while she was changing a tire.

Her death was originally ruled an accident, as was Toni's. But Henthorn took out an insurance policy on Lynn's life, as he did with Toni. In fact, prosecutors in the second death case say there were three policies in Toni's name, each calling for a payoff of approximately $1.5 million — and for one of them, Henthorn was the sole beneficiary.

The prospect that Henthorn killed not one but two wives by making their deaths look like accidents explains why the case received such national notoriety; below, see numerous videos from an edition of CBS' 48 Hours devoted to it. But the tragic losses remain very personal for many of those who spoke today at the sentencing hearing, including Toni's father, brother and a representative of the couple's ten-year-old daughter, Haley.

According to 7News, the girl's guardian ad litem says she's doing well — but she also fears that she "might grow up to be like her father." Perhaps that's why she no longer refers to Henthorn as her dad.

As for Henthorn, he stayed consistent, insisting that he'd done nothing wrong. Before the sentencing, 9News quotes him as saying, "Toni was a remarkable woman. I loved her with all my heart. I did not kill Toni or anyone else."

Afterward, Henthorn was led from the hearing in handcuffs to begin serving his sentence — but this may not be his last trip to court. Prosecution for Lynn's death remains a very real possibility.

Continue for one of our earlier reports, featuring much more information about the case.

And Saturday, the tragedies were the subject of a 48 Hours investigation on CBS that supplemented the shocking details with a wealth of photos and videos, including one shot by Toni's coworkers to capture her surprise at learning about the trip to Rocky Mountain National Park — one that would end days later with her death.

As we've reported, a request for order filed by U.S. Attorney John Walsh, who's in charge of prosecuting the case because Rocky Mountain National Park is federal land, stated that "on September 29, 2012, Harold Henthorn's wife Toni Henthorn fell to her death with Harold Henthorn as the only witness, in a remote location in Rocky Mountain National Park, Colorado." Walsh added that " investigation has revealed there are three $1.5 million life insurance policies on Toni Henthorn, two of which are in trusts, and one in which Harold Henthorn is the sole beneficiary."

This isn't the only circumstance Walsh sees as suspicious. In the document, he implied that Harold was living off Toni, a respected ophthalmologist, while conducting a mysterious double life. Here's a key passage:

Harold Henthorn travels frequently, even weekly, allegedly for work. However, there is no indication that he has actual clients. He has no business in his name, no partners able to be located by law enforcement to date, and no one interviewed to date knows who his clients are or were, yet he told investigators he was financially secure, and he was a fundraiser for nonprofits like churches and hospitals. At his wife's funeral witnesses told investigators there were no attendees from Harold Henthorn's work and witnesses interviewed by investigators revealed no one actually knew what his business was called, or any of his projects or clients.

Was Henthorn capable of murder? Walsh floated that possibility by pointing out that "in 1995, Harold Henthorn's prior wife" — Sandra Lynn Henthorn — "died from injuries sustained from being crushed by a car while he was changing a tire in a remote location. The car allegedly came off the jack as he was throwing the tire in the trunk, crushing his wife, who was under the car for unknown reasons. There were no witnesses other than Harold Henthorn and a life insurance policy on her had been taken out several months prior."

Upcoming Events

While Lynn's death was initially deemed a tragic accident, Douglas County investigators reopened the case last fall.

Meanwhile, Walsh cited what could have been another attempt by Harold to kill Toni in a way that would have seemed accidental. He wrote:

In early September or late August of 2011, a beam hit Toni Henthorn on her head while working on her cabin with Harold Henthorn, fracturing her vertebrae. The beam fell off the porch where Harold Henthorn was working, after he called her to come help him. Toni Henthorn told her mother, "If I hadn't bent down after I walked outside, the beam would have killed me." This is another accident in which Harold Henthorn was the only other witness."

More detailed accounts of these incidents were featured in the search warrant, supplemented by tales of other curious incidents. For instance, investigators found "a National Park Service map of Rocky Mountain National Park...which had the Deer Mountain trail highlighted in pink highlighter and an 'X' marked near the location where Toni Henthorn fell to her death," allegedly after slipping while trying to take a photo.

The first time Harold was asked about the map, he's said to have been "at a loss for words."

In addition, one acquaintance said Harold had confided that he had "taken six different hikes at Rocky Mountain National Park, about two weeks before [Toni's death], trying to find the hike to take Toni on their anniversary weekend. Henthorn told her he planned every minute of their trip."

48 Hours exploration of these issues is illustrated by images such as this portrait of Toni....

The result is a disturbing look at a man authorities believe was a monster hiding in plain sight.

Look below to see three videos from the episode.

The first features the aforementioned cell-phone video of Harold surprising Toni. That's followed by comments from Toni's niece, who says her beloved aunt's death opened her eyes to Harold's true self. More memories of Toni are spotlighted in the third clip, while the fourth features the program in its entirety.